This disclosure is based on a glow plug comprising a casing, a ceramic glow pin protruding out of the casing and having a tapered end section inside the casing, a protective tube which is made of metal and protrudes out of the casing and surrounds the glow pin, a center electrode, which is arranged in the casing and electrically connected to the glow pin, and an annular or sleeve-shaped contact element, through which the glow pin projects and to which the tapered end section of the glow pin is soldered. Such a glow plug is known from U.S. Publication No. 2011/0215080 A1.
Ceramic glow pins are susceptible to fractures and are therefore protected by a protective tube which is made of metal and projects out of the casing of the glow plug. The ceramic glow pin sits in the protective tube and projects with its combustion chamber side end, i.e., the glow tip, out of the protective tube. In the casing, the glow pin is electrically connected to a center electrode via a tapered end section. This tapered end section is surrounded by an annular or sleeve-shaped contact element which on its inside is shaped to fit the tapered end section, and soldered to the same. Generally, the glow pin is thus connected via the center electrode to potential and via the contact element to earth.